(5S,8S)-8-[{(1R)-1-(3,5-Bis-(trifluoromethyl)phenyl)-ethoxy}-methyl]-8-phenyl-1,7-diazaspiro[4.5]decan-2-one (the compound of Formula I; also referred herein as Compound 1) and salts thereof have been described in U.S. Pat. No. 7,049,320 (the '320 patent), issued May 23, 2006. A process for the synthesis of Compound 1 is specifically exemplified in Example 72a of the '320 patent (See the '320 patent at col. 43, line 55 to col. 45, line 20; col. 75, line 55 to col. 80, line 21; col. 90 lines 35 to 63; and col. 98, line 1 to col. 99, line 24, which is herein incorporated by reference. See also WO2008/11833, Examples 1-6, which are herein incorporated by reference). WO 2005/063243 discloses certain pharmaceutical compositions comprising NK-1 antagonists. The formulations described therein require a polyanionic beta-cyclodextrin derivative with about one to seven sodium sulfonate groups separated from the lipophilic cavity by at least one butyl ether spacer group—i.e., Captisol®. There is no reference therein to iv formulations which minimize hemolysis. In addition, various salt forms of a compound of Formula I have been described in, for example, U.S. Pat. Publication 2007/0244142 and which is also incorporated by reference.

The compound of formula I is classified as a tachykinin compound and is an antagonist of neuropeptide neurokinin-1 (NK-1) receptors. The compound of formula I may be in the form of a free base or in the form of a pharmaceutically acceptable salt. The free base or salt may be in the amorphous form or the pharmaceutically acceptable salt used herein may be in a crystalline form or crystalline hydrate or solvate form. In solution and depending upon the pH of such solution, the compound of formula I may be in the form of a mixed free amine/salt form. Prodrugs of a compound of formula I may also be utilized in the formulations suitable for parenteral administration. Prodrugs wherein either free amine (or both amines) in a compound of formula I has the hydrogen replaced with a group selected from —Y and salts thereof wherein Y is selected from —P(O)(OH)2, —S(O)n1R1, —C(O)(C1-6alkyl)X, —C(O)(C1-6alkyl)(aryl), —C(O)OR4; X is selected from —NR2R3, —P(O)(OH)2 or —S(O)n1R1; R1 is H or C1-6alkyl; R2 is H or C1-6alkyl; R3 is H or C1-6alkyl; R4 is H or C1-6alkyl; n1 is 0-4 are suitable for use herein. Suitable cations or dications for the ionized form(s) of the prodrugs include metal salts or organic amine cations including meglumine salts and the like (N-methyl D-glucamine). Such prodrugs may be utilized with or without the described parenteral delivery vehicles in a suitable liquid formulation to treat patients in need of treatment thereof. Such prodrugs are converted to the non-prodrug form of the drug (or salt thereof) upon parenteral administration to the patient. Such prodrugs may be in amorphous form or in crystalline and/or crystalline solvate/hydrate form.
NK-1 receptor antagonists have been shown to be useful therapeutic agents, for example, in the treatment of pain, inflammation, migraine, nausea, emesis (vomiting), and nociception.